The Array Core will provide arrays and associated services for analysis of DNA copy number variation (array CGH) and gene expression. Array CGH: The arrays for CGH analysis will consist of BAC clones distributed at approximately 1 Mb intervals over the genome. These arrays allow reliable detection of single copy changes from diploid as well as high-level amplifications. Arrays for human and murine analysis will be provided during the grant period. In addition to these standard arrays, the Core will make custom BAC arrays for individual projects, provide instruction on use of the BAC arrays (DNA isolation, labeling, hybridization, imaging and analysis), and consultation on interpretation of data. It will also offer a full analysis service, receiving DNA from investigators and returning data. Gene Expression: Oligonucleotide arrays will be offered for gene expression analysis. The Core will provide instruction in the use of these arrays (RNA isolation, labeling, hybridization, imaging and analysis), and consultation on analysis and data interpretation. It will also offer a full analysis service, receiving DNA from investigators and returning data. Custom expression arrays consisting of cDNAs or oligos will be produced for individual investigators using reagents that they provide. Instrumentation: The Core operates two array imaging systems, an Axon 4000B and a custom built CCD camera system, and a high-speed array printer. In addition it has two laboratory robots to assist with re-arraying and preparation of printing solutions.